Selective signaling apparatus



H. HULL. SELECTIVE SIGNALING APPARATUS. KPPUCATION FILED JUNE 25, 19l4- RENEWED NOV. 30, I918.

Patented Oct. 14, 1919.

9 SHEETS-SHEET 1.

MM 0 Aneo w H. HULL. SELECTIVE SIGNALING APPARATUS. APPLICATION FILED JUNE 25, I914- RE NEWED NOV. 301I9I8| Patented Oct. 14,

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h 2 g 0 HIHHJ H. HULL. SELECTIV E SIGNALING APPARATUS. APPLICATION FILED JUNE25| l9l4- RENEWED NOV- 30' I918.

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SELECTIVE SIGNALING APPARATUS.

APPLICATION FILED JUNE 25, I914. RENEWED NOV. 30. I918.

1 ,3 1 8,670 Patented Oct. 14, 1919.

I a SHEETSSHIEET 4.- 1 2 .4 a 90 9' 5f 66 me f Z6 H. HULL. SELECTIVE SIGNALING APPARATUS. APPLICATION FILED JUNE 25. 1914. RENEWED NOV-30,19l8. 1,318,670.

Patented Oct. 14, 1919.

9 SHEETS-SHEET 5.

H. HULL. SELECTIVE SIGNALING APPARATUS. APPLICATION FILED JUNE 25. 1914. RENEWED NOV. so, 1918.

Patented Oct. 14,1919

9 SHEETS-SHEET 6- flora c e //u (d Nu E H. HULL.

SELECTIVE SIGNALING APPARATUS. I APPLICATION FILED JUNE 25, 1914- RENEWED NOV. 30, 1918. 1,318,670. Patented 0@t.14,1919.

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uh-Two H. HULL. SELECTIVE SIGNALING APPARATUS. APPLICATION FILED JUNE25. 1914. RENEWED NOV. so. 1918. 1,318,670.

Patented Oct. 14,1919.

9 SHEETS-SHEET 8- H. HULL.

SELECTIVE SIGNALING APPARATUS. APPLICATION FILED JUNE 25, I914. RENEWED NOV-30,1918.

1 ,3 1 8, 670 Patented Oct. 14, 1919.

9 SHEETSSHEET 9.

HORACE HULL, OF DENVER, COLORADO.

SELECTIVE SIGNALING APPARATUS.

Specification of Letters Patent.

Patented Oct.14, 1919.

Application filed June 25, 1914, Serial No. 847,272. Renewed November 30, 1918. Serial No. 264,862.

To all whom it may concern:

Be it known that I, HORACE HULL, a citizen of the United States, residing at Denver, in the county of Denver, State of Colorado, have invented certain new and useful Improvements in Selective Signaling Apparatus; and do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to. signaling apparatus, and while I have in the present instance illustrated and described my invention as embodied in its preferred form, that is to say in a selective telephone system, I wish it to be understood that it is not limited in its useful application to this particular purpose, as it may be employed in connection with other signaling systems, such as telegraph, block signaling systems, and the lik I Briefly, my invention embodies, among other features, a selective signaling system having a plurality of signaling stations connected in multiple with a main electric circuit and employing alternatingcurrent as the electric energy for operating the select ing apparatus of the system.

In the telephone system set forth herein, by way of showing one applicationof my invention, the station of the party calling is to be considered the sending station and the station of the party receiving the call is to be considered the receiving station. Theremay be any number of these stations connected-in multiple with the line or circuit, for example twenty or more, and each station is equipped with a selecting apparatus which includes both mechanism for send ing a call and mechanism for receii'ing a call. Therefore, where I hereinafter use the expression selecting apparatus I mean to include both the sending and the receiving mechanism, While where I use the term sending mechanism it means only the sending part of the selecting apparatus, and where I use the term receiving mechanism, it means only the receiving part of the selecting apparatus. y

In carrying out my invention it is my purpose to provide a selective signaling system suchas a telephone system. wherein a plurality of stations are connected in multiple into an electric circuit, and wherein alternating current is employed as the elec-v necessitating high amperage.

known. with a direct current of high ampertric energy for operating the selecting ap-- paratus of the system. By using alternating current for operatlng the selecting apparatus, I dispense entirely with the use of direct current for this purpose, and I am thus enabled'to connect a relatively large number of stations in multiple with a main circuit or line so that I may operate the selecting apparatus over the same Wire I use for other purposes, such for instance as for the talking circuit of a telephone system.

Further in the practice of the invention as illustrated herein, I provide a selector apparatus operating with impedance coils connected in multiple with the main circuit and operated by alternating current, the carrying of a direct current over the line being dispensed with, so that my selector apparatus Will operate on a ground return circuit.

By employing alternating current ih' the operation of my system I avoid the expense and disadvantage incident to the employment of direct current in systems oflthis character. IVhere a direct current is used, a coil of high resistance cannot be employed,

and therefore, the direct .current coils can-' not be connected in multiple with the line, the consequence being that it is necessary to use a separate wire to select over from that which is used for the talking circuit or else the talking circuit must go through the direct current coils; There are numerous other advantages incident to the use of alternating current in comparison with direct current in apparatus of this character.

\Vith alternating current equipment, the alternating current generated is. of course of high voltage and very low amperage, so that the line offers very little resistance to a current of this nature, whereas with a direct current the selecting mechanism would require such direct current to be of high voltage and also high amperage, as such a direct current must produce the energy or power to operate the selecting apparatus in the cores of the wound magnets, thus As is well a e a. coil of high resistance cannot be used,

and thus in, systems of this character direct I current coils cannot be connected in multiple with a line, so that in telephone Work, for instance. separate lines are required for selecting and talking. Therefore, in. using direct current on a system not em loying a central station, the expense wou d necessarily be great, as each sending station would have to be equipped with a source of direct current suflicient to operate the entire system. Therefore, owing to the expense in connection with the use of direct current, it is'the practice to make selections by employing a central station, while on the other hand by using the alternating current the whole cost of the equipment is so small that every station may be equipped with a source of alternatingv current, thus rendering it unnecessary to operate with a central station in case where all parties are on the "*same line.

It will further be understood that the use of alternating current for this purpose posesses many advantages over the use of direct current in the cost of mechanism, in the feature of long distance work, simplicity of construction, facility of operation, and many other features readily apparent to and understood by those skilled in the electric art.

' A further object of the present invention is the provision of a signaling system, such as a telephone system, wherein a plurality of telephones are connected in multiple into an electric circuit, and wherein a party at one telephone may signal and converse with a party at another or selected telephone in the circuit without signaling any other stations which may happen to be on the same line.

Another object of this invention is the provision of an apparatus of this nature and adaptation whereby a person at any one of a number of stations connected in multiple into an electric' circuit, upon selecting and signaling any other one of said stations, automatically locks off all of the remaining of said stations, except the one desired.

Another object of the invention is the provision of a system of this character whereby two or more stations connected in multiple into an electric circuit may select another of said stations and automatically place such selected station into the talking} circuit with the said two'ormore stations.

It is also my purpose to provide a system of the character described wherein a plurality of telephones-are connected in multiple in an electric circuit and wherein a,

central station may be employed for the purpose, of connecting and disconnecting parties on different lines, the construction and arrangement of parts being such that any party on the line may be connected to and disconected from the circuit at any time at the will of the operator at the central station.

With the above recited objects and others of a similar nature in view, myinvention. consists in the construction, combinat on-'- and arrangement of parts set forth in and aezaere falling within the scope of the appended claims.

In the accompanying drawings:

Figure 1 is diagrammatic view of the circuits and equipment of three subscribers stations on the same line, with two of the stations connected and an intermediate station disconnected, the connected positions of the two stations being shown by dotted lines.

Fig. 2 is a diagrammatic view illustrating two subscribers stations on different lines and a central station through which connection is made between the two subscribers stations, the connected positions of the stations being shown by dotted lines.

Fig. 3 is a View in front elevation with thecover or face plate of the box of the selector apparatus removed, this view showing the receiving and sending mechanism of a selecting apparatus in open or idle position.

Fig. 4 is a view partly in side elevation and partly in section showing more particularly the receiving mechanism of the selecting apparatus shown in- Fig. 3.

Fig. 5 is a similar view showing more particularly the sending mechanism of the selecting apparatus shown in Fig. 3.

Fig. 6 is a view showing the position occupied by certain of the working parts of the selecting apparatus when a call has been made from the sending station of the apparatus, certain parts ofthe apparatus being omitted for the sake of clearness.

Fig. 7 is a similar view showing the locked out position of'the same working parts of the selecting apparatus of a dead or disconnected station when connection has been made between two'other stations.

Fig. 8 is a similar view showing the position occupied by the working parts of the Selecting apparatus at a receiving station. when such station has been called.

Fig.9 is a sectional view of the apparatus, shown in Fig. 3 with certain parts omitted,- and showing more particularly the push rod for the receiving mechanism, the local battery switch and the gear segment and pinion therefor of the receiving mechanism.

Fig. 10 is a plan view with the casing of the box in section and showing the selecting apparatus of Fig. 3 and the alternating cur-' rent coils for operating the e'scapement of the apparatus.

' Fig. 11 is a detail view in bottom plan showing the cam and lock member of the receiving mechanism.

Fig. 12 is a detail perspective view of a portion of one of the escape wheels.

Fig. 13 is a detail view of the bell and alternating current generator switches connected .to their rock shaft.

preferred form of telephone embodying my invention.

'i'.. .F-ig. 14 is a view in front elevation of a I Fig. 15 is a view partlv in front elevation and partly in section of a portion of a central station and showing parts of'the receiving mechanism of a selecting apparatus at the central station, as well as the arrangement of the signal lights at the station.

Fig. 16 is a. detail diagrammatic view furtherillustrating a portion'of the apparatus and the signal light circuits at the central station;

Fig. 17 is a View partly in section showing more particularly the Sending mechanism of the central station.

Fig. 18 is a detail view in top plan show- ;ing the two esca e wheels of the selecting apparatus and tie escape rod and pallet therefor. 1

Fig. 19 is a diagrammatic view showing the alternating current switches and coils connected in multiple with a main circuit.

Fig.20 is a detail perspective view of a portion of the selecting apparatus showing the alternating current and local battery switch 011 their rook shaft and the position of the locking rod to allow-the closing of these switches.

In the present instance I have shown two adaptations of my invention, one wherein a plurality'of telephone stations are connected in multiple on the same circuit, so that any party on that circuit may talk to any other party on the same circuit without resorting to a central station so hat-under this condition a central station may be dispensed with entirely. In the other adaptationshown and describeda central station is used so that parties on different circuits or lines may communicate with each other.

For the sake ofclearness I will first describe in 'detail the construction. ando )eration of that adaptation of the system w erein the stations are 'all' in the same line, and no central station is required. In this con.- nection reference is to be made to all the figures of the drawings, with the exception of Figs. 2, 15, 16 and 17 which latter figures relate to the system when equipped with -a central station. i

In Fig. 'l'I have shown diagrammatically one arrangement of circuits and electric equipment for enabling parties on the same line to communicate, and in'i-this view I show the system as-including three stations 3, 4 ando, and m 'conslderlng these stations here-' affe-r,.we' will consider that the number 3 is the call :nmnber of the sendin station, the number 4 the call number of the intermediate or locked outstation, and number 5 the call number of the receiving or called station. In this Fig. 1,.the stations 3 and 5 are connected for service, as indicated-by dotted lines, while intermediate station 4 is on an open-circuit or dead-,"in the sense tliatf-j While parties 3 and 5 may converse, a party at I cannot cut in on the .c 'rcult to overhear the conversation, or for anyother reason.

The line wire of'the circuit is shown at 90, while the return is indicated at y.

Each of the stations is equipped with a telephone T, having the usual transmitter t, receiver 1 and receiver hook it, as shown in Fig. 14. The telephone casing is indicated by the letters D, while I) is the usual bell. The casing is equipped with the .usual hinged lid 03 closing the compartment of the casing wherein is located the alternating current generator g operated by the crank g. The use to which I put this generator will he hereinafter described in detail. compartment with the generator is also located the condenserc, as usual. The ordinary local battery 104 for setting up the talking circuit is also located as usual in the casing D, but as will be hereinafter described, I also use this local battery for operating the bell b. The induction coil 2' is also located in the. casing, as usual.

Within the To the front of the lid 03 is connected or attached a box E wherein is located the selectmg apparatus which constitutes an essential feature of my invention, and the construction of'which is shown in detail in Figs. 3 to 14 inclusive and also Fig. 20.

I will now proceed to describe the structural features of the selecting apparatus, referring particularly to Figs. 3, 4, 5 and 10. Subsequently I will describe in detail the operation of the entire system, including the various circuits thereof. The selector ap paratus is indicated as'an entirety by the letterF, and includes a sending mechanism designated as a whole by the letter S, a receiving mechanism indicated as a whole by the letter R and certain operating parts, including an escapement device which isinterposed between the sending mechanism and the receiving mechanism for the purpose hereinafter described. the entire selecting apparatus being mounted between the front and back nlates l and 2 respectively which constitute a suitable support for the working parts of the apparatus.

The sending mechanism S includes a thumb wheel 3 loosely mounted on the post 4* connecting the plates 1, and 2, the pin 5 carried by the wheel having one end of a spring 6 connected therewith, said spring being coiled about the post .4? with its opposite end connected to the post at 7. This thumb wheel 3 projects through a slot 8 in the side of the box E soit maybe easily manipulated. The thumb wheel 18 toothed and meshes with a pinion 9 fast on the shaft 10 which shaft has also fast therewith the arm 11. This arm 11 has a dog 12 pivoted thereto, and engaging with a ratchet wheel ratchet wheel. This ratchet wheel 13 is fast with one side of the escape wheel 15 loose on .13 loose on the shaft 10, a spring 14 normall "holding the dog in engagement with the the shaft 10, this escape Wheel having two rows of circumferentially arranged teeth, the row of teeth indicated at 16, being in staggered relation to the other row of teeth indicated at 17 as will be clearly seen by reference to Figs. 12 and 18. At the front end of the shaft 10 is fastened an indicator hand 4), which moves over a dial 4) having a row of indicating numerals 'v thereon, as shown in Fig. 14. WVhen the thumb wheel 3 is turned by a person desiring to make a call, the hand 41 moves over the dial to the selected number and thus indicates the. number of the station it is desired to,call. For instance, if a party at station 3 desires tocall a person at a station 5, he turns the thumb wheel 3 until the hand '0 reaches the number 5 on the dial. This turning of the thumb wheel, rotating the shaft 10 as it does, turns the arm 11 anti-clockwise, for the purpose hereinafter mentioned. The escape wheel 15 being loose on the shaft 10 does not turn therewith, and is prevented from being carried around anti-clockwise with the arm 11 and the dog 12 by the leaf spring 18 which is fastened at one end to the back plate 2 and engages at its free end with this escapement wheel 15, as shown in Fig. 9. The numeral 19 indicates a rock shaft journaled at its rear end in the back plate 2 and at its front end in the metallic bar 20 carried by the insulating block21 connected with, and extending forward from the back plate 2, as is best shown in Fig. 10. Depending from this rock shaft 1 19, is an arm 22 terminating at its lower free end in a loop 23. A pin 24 extends from the arm 11 and is adapted to strike against the arm 22 at the loop thereof and rock the shaft 19 so as to move the horizontal contact switch 25 downward away from the contact pin 26 which extends through the insulatin block 21 and is connected above the bloc with the conductor 27. As there are two contact switches connected with the rock shaft 19, one of which is designated by the number 25, and is used to open and close the alternating current circuit, and the other of which is numbered,84 and is used to open and close the local battery or bell circuit, I will hereafter call the switch 25 the alternating current switch, and call the switch '84 the bell switch. The switch 25 is socketed in the insulating block 28 carried by the rock shaft 19, while 29 is a coiled spring normally tending to throw the switch 25 into contact with the contact pin 26, the spring being coiled about a portion of the rock shaft 19 with one of its ends fastened to the rock shaft and the other end secured to a stud 30 projecting from the back plate 2.

The above is a description of the structural features of the sending mechanism S of the selecting apparatus F of each station. Now, when a party making a call, say from emma station 8, lifts the receiver r, turns the thumb wheel 3 of thesending mechanism to the number on the dial of the station wanted, in the present instance station 5, and rotates the generator crank g, the receiving mechanism Rat such reeeivin station 5 is operated to close the talking circuit at that station and simultaneously close the local battery or bell circuit at the receiving station 5, to cause the hell I) thereat to ring. At the same time the operation of the sending mechanism S at the calling or sending station 3 operates the receiving mechanism R of its own station to close the talking circuit of said sending station, as hereafter described.

The receiving mecham'sm.- -I will now proceed to describe the construction of the receiving mechanism R of each station. Referring to Figs. 3 and 14, the numeral 31 designates a winding arbor, to which is connected one end of the coiled main spring 32, the opposite end of the spring being connected to a post 33 carried by the back plate 2, the main spring 32 constituting the usual spring motor. This spring is confined against lateral displacement by the back plate 2 and the circular holding plate 33 placed in front of the spring as shown in Figs. 4 and 5. Loosely mounted on the' arbor 31 is a gear wheel 34, carrying a pawl 35 which engages with the ratchet wheel 36 fast on the arbor 31. lVhen the arbor 31 is turned to wind up the mainspring the pawl'and ratchet wheel preventthe backward rotation of the arbor. But when the main spring is unwinding in driving.

the shaft 42 driving the latter. The shaft 42 has fast therewith the escape-ment wheel 43, the gear segment 44, the collar 45 carrying the contact pins 46 and 47, and the cam 48, the latter being at the rear of the escape wheel 43, as shown in Fig. 11. I'will state here that the contact pin 46 is employed to close the talking and bell circuits when the telephone is used as a sending or calling station, while the contact pin 47 is used to close these two circuits when the telephone is used as a receiving or called station, as will be herein described.

. The escape wheel 43 has two segmental rows of teeth 49 and 50, arranged in stagge ed relation, or similar to the teeth 16 an 17 of the escape wheel 15 as shown in Figs. 12 and 18. a portion of the periphery of this escape wheel 43 being devoid of teeth as at'51. Fast on the shaft 52 is a pinion 5?- with which meshes the segment gear 44 at certain times to rotate the shaft 52 through this pinion 53, the shaft 52 having fast therewith a gear wheel 54 which meshes with the pinion 55 of the shaft 56 turning the latter and consequently the gear'wheel 57, which is fast with the shaft 56. This gear wheel 57 meshes with a pinion 58 fast on the fan shaft 59, the latter carrying a fan 60. which is used as a governor fan to govern the speed of rotation of the escape wheel 4-3 when the toothless section 51 of the escape wheel is passing the pallet 87 at which time the segment 44 is in mesh with As shown in Fig. 11, the cam 48 on the shaft 42 rides against the slmuldered end 61 of the arm 62 carried by the small rock shaft 63 which has depending therefrom the locking arm 64 having a lateral end 65 adapted to engage the teeth of the gear wheel 54 as long as the cam continues to bear against the end 61 of the arm 62, which isjust so long as the segmental gear 44 is in mesh with the pinion 53. \Vhen. however, the segmental gear moves away or off from this pinion, as shown in Fig. 9, the cam 48 will move from under the arm 62 permitting the spring 66 to throw the arm 64 and cause its end 65 to engage the gear wheel 54 and lock it against further rotation. The purpose of locking this gear wheel 54 after the segn'ient gear 44 has left its pinion 53 is to hold the pinion 53 in proper position for the next engagement of its segment gear44. It is to be noted that the segmentgear 44 only engages with the pinion 53 at the time when the section 51 of the escape wheel 43 is passing the pallet 87 of the escapement device, and as the pallet cannot at this time engage and the pinion govern the movement of the escape wheel 43, the segment 44 will do so as it 15011 the same shaft 42 as the escape wheel '43 and engages the pinion 53 of the governing train of gearing at the time mentioned.

Extending from the back plate 2 is a stud shaft 67 having loosely mounted thereon a sleeve 68 provided with flanges 69 and 70. Depending from the flange 69 is an arm 71- adapted at certain times to be struck by the pin 72 projecting laterally from the escape wheel 43,. so that the arm 71 will be moved to rock the sleeve 68 and depress the locking rod T3attached at one end of the flange 70. Thi rod 73 which is preferably made of wire, extends horizontally across to the sending mechanism S. the rod passing through the loop 23 of the arm 22. This locking rod '73 is formed at its outer end with a depending hook 74. The locking rod is further provided with a locking block 76. This block. when the telephone is not in use lies just to one side of the loop 23 and in alinement or centered therewith, as in Fig. 3 so when the thumb wheel 3 is turned in making a selection the loop 23 will be thrown over the block 7 6, as shown in detail in Fig. 20. \Vhen the talking circuit is closed, the locking block 7 6 at the sending station 3, will lie depressed at one side of the loop 23, as shown in Fig. 6, while at the same time the counterpart locking blocks 76 atthe stations 4 and 5 and any other stations on the line, will be elevated and lie at one side of the loop 23 as shown in Fig. 7. The reason for this will be set forth in the description of the operation of the system. A coiled spring 77 normally tends to throw the locking arm 73 to its elevated position as shown in Fig. 4. The numeral 11 designates astop pin projecting from the back plate 2 which pin is designed to limit the anti-clockwise rotation of the arm 11 so that after the pin 24 on the arm has struck the hook 74' of the locking rod 7 3 sufficiently to raise the latter and permit loop 23tostraddle block 76 and allow switch 25 to close, such arm 11 will be stopped from further movement by the stop pin 11, and

the liability of the arm 11 continuing its 43. When the thumb wheel 3 is turned in making a selection and the rock shaft 19 consequently rocked by its spring 29, this latching bar 7 8 will engage at its offset end with the pin 80 of the escape wheel 43 and hold the latter against rotation.

- Extending through the insulating block2l are the spaced contact plates 81 and 82 wlnch are connected with the conductors 27 and 27, respectively, these contact plates being adapted to be. bridged ouconnected by the contact pins 46 and 47 to close the talkmg and bell circuits. The contact plate 82 is further connected through its wire 27 with the contact pin 83, the latter being designed to be contacted with by the contact arm 84 carried by the rock shaft 19 to close the local battery circuit through the bell.

Fast with the front' end of the shaft 42, as shown in Fig. 14, is an indicator hand 20 which moves over the dial w, the'latter con.- stituting the indicating dial of the receiving ide of the telephone. This indicating dial is provided with a row of numbers 10", these numbers on the receiving dial corresponding to the numbers on the sending dial of the apparatus.

The escapement device includes avertically disposed rocker bar 85 mounted to turn in bearing studs 86-projecting inward from the back plate 2.- This bar extends vertically between the two escape wheels 15 and 43 and is provided with oppositely disposed pallets 87 and 87 adapted to engage the teeth on the peripheries of the escape wheels 43 and 15 respectively. Screw studs 88- are mounted in the back plate 2, and act as adjustable stops for the pallets 87 and 87 to limit the rocking movement of the bar 85. The numeral 89 designates an arm connected to the rear of the bar 85 and this arm project's through an opening 90 cut in the back plate 2. This arm is for the purpose of rocking the escapement bar 85 and it is actuated as follows: The outer end of the arm 89 terminates in a loop 91 through which projects the free end of the armature rod 92. This armature rod is rigidly connected at one end to the rocking armature 93 of the alternating current coils 94, the numeral 95 indicating the permanent. magnet of the alternating current coils. The alternating current coils and their magnet are fastened to the inner side of the telephone lid (2 by the soft iron supporting bar 96, which is slotted to permit of the vibration of the armature rod 92.

Referring to Fig. 9, the numeral 97 indicates a reciprocating or push rod sliding through an opening in the shaft 4 and through an opening in the guide stud 98,, the outer end of the rod extending through the side of the box E and having a push button 99 at the outer end thereof by means of which the rod may be pushed inward to have its end 100 engage with the teeth of the escape wheel 43 to lock such Wheel againstmovement when it is desired to put a third party on the line, so that all three parties may confer. A spring 101 normally holds the rod 97 out of contact with the escape wheel 43. Legs or studs 102 are used to hold the back plate 2 to the back of the box IE and thus support the selecting apparatus in the boX. t a

The above is a description of the mechanical construction and the relative location of the various parts which go to make up the selector apparatus F, including the sending mechanism S and the receiving mechanism,

R, and I will now proceed to describe in detail the operation of that embodiment of the system as is diagrammatically illustrated in Fig. 1, wherein I have shown three stations connected in multiple in one main circuit, such system dispensing with a central station, which figure also embodies the electrical circuits. Fora clear understanding of the invention in Fig. 1 I have shown a system embodying three stations or telephones on the same line, and each of these stations is equipped with similar apparatus, that is to say, a telephone which in addition to the usual equipment of the transmitter,

' receiver, and the like, is provided with my selecting apparatus. In this case We will assume that the party at the first station 3 wishes to talk to the party at the third sta-, tion 5, so that theparty at the second station 4 is to be cut out. The party at station 3 desiring to call station 5, now proceeds as follows: I

When the entire line is clear, that is to say, when none of the stations or telephones are in use, the parts of each selecting apparatus F are in clear or open position as shown in Fig. 3, and the circuits are open as shown in full lines in Fig. 1. At this time the indicator hands 2 and w of the receiving and sending dials of each apparatus lie as is shown in Fig. 14, that is to say, at the point marked open line. Now, the first thing the calling party at the station 3 does is to lift the receiver r from the hook 7b,. allowing the hook lever which also constitutes part of the usual receiver switch, to move up away from the receiver contact point 103 and thus break the local battery circuit or bell circuit to'pre-vent the ringing of the bell of the sending station 3. By reference to Fig. 1, this local battery or bell circuit for the sending station may be traced from the battery 104 through the conductor 105 to the receiver hook it which forms part of the switch, thence when the receiver hook is down, through the contact point 103, concuit and this is the reason the receiver 1' should be lifted" from the hook before the thumb wheel is turned, as otherwise the .bell would ring at the station 3 and cause annoyance. By lifting the receiver from the hook, however, the hook leaves the contact po nt 103 and breaks the bell circuit at the station .3.

, Now the actuation of the generator 9 from the sending station 3 closes the local battery or bell circuit at station 5 by causing pin 47 to move into bridging or contact position between the contact plates 81 a'nd82 at station 5, and the closed local battery or bell circuit at this receiving station 5 may be traced as follows: From the battery 104 at station 5, the current passes through conductor 105, to receiver hook it which is down,

through contact 103, conductor 106, to conductor 107, to conductor 27, contact plate 82,pin 47, to conductor 108, to conductor 109, through bell b,*through conductor 110 and conductor 111, to the battery 104. This is the bellor signal circuit at the receiving station. When the receiver is lifted from its hook hat the receiving station 5, this circuit is opened or broken and the bell will cease to ring. I

After lifting the receiver 2', the party calling from station 3 turns the thumb wheel 3" until the indicating hand 1) of the sending dial points to the number 5 on the dial,-

this being the call number of station 5. lVhen the thumb wheel 3 is so turned, three thingswill take plac'elin the selecting apparatus. The alternating current circuit is closed for the generator and bell; the latching arm 78 moves into position ready to hold the escape wheel 43 of the receiving mechanism of the sending station 2'; and the arm 11 at the station 3 is moved anti-clockwise a predetermined number of teeth. In other words the turning of the thumb wheel 3 and the consequent rotation of the gear wheel 9 causes the rotation of the indicating hand to'move the latter over the dial to the desired number 5. At the same time the shaft 10 ro= tating carries. with it the arm 11, the dog 12 slipping over the teeth of the ratchet wheel straddle the locking block 76. At the same 9 so that the ratchet wheel and its escape wheel 15' remains stationary. Now, the in-' stant the arm 11 starts to move, toward the left the pin 24 of said arm, of course, moves away from contact with the depending arm 22 and the spring 29 immediately rocks the shaft 19 to let the loop 23 of the'arm 22 time .the partial rotation of the rock shaft 19, under the. influence of the spring 29 throws the contact switches 25 and 84 against the contact pins 26 and 83 respectively to close the local battery or hell circuit heretofore described, and also closes the alternating current circuit from the generator 9 to the main wires :0 and y. This turning of the rock shaft 19 also moves the latching arm 78 upward so that the offset end 79 of the latching rod will be moved into alinement with or in front of the pin 80 carried by the escape wheel 43 of the receiving mechanism of the selecting apparatus.

Now, when the alternating generator circuit has been closed by the contact of the switch 25 with the contact pin 26, and the crank g of the alternating current generator g is turned to excite the latter and set up the alternating current, said current will flow from the generator 9, through the conductor 112 to the switch 25, contact pin 26, conductor 27, conductor 113, to the line wire w. A portion of the current is shunted off through the alternating current coils 94 of each station on the line. In making the shunt the current passes from the conductors 113, to conductors 114 through each set of coils 94, and after passing through the coils flows through the conductor 115 and conductor 116 to the return line 7 along whi h the current passes to the conductors 117 and 118 back to the alternating current require six cycles.

generator from which it started. 1 hile the return wire 3 1s herem shown in the nature or a metalllcreturn, it is to be understood that the ground would serve the same purpose.

Now, referring to the example presented,

cuit is clear or not in use, and at this open a line position of the telephone, the contact pin 46 of each telephone is just one step or space back of the contact plates '81 and 82, that is to say it takes just one cycle of the alternating current or one complete vibration of the armature by the coils 94 to bring all pins 46-into bridging position between the contacts 81 and 82, and when the dog12 moves a notch on the ratchet 13,

this correspondsto one cycle of the alternating current, which causes one complete vibration of the escape rod 85. It is to be noted that the pins 46 of all the stations are set in the same relative location on the collars 45, that is to say, when the line is clear all of the pins will be just one step .or space backof their adjacent contact plates 81 and 82- as shown in full lines in F ig.-1. On the contrary, the contact pins 7 47 of the stations are all located at different positions on their collars relatively to each other, that is .to say each pin47 will require a different number of cycles of the alternating current from every other pin 47 to bring it into bridging contact between the plates 81.. and 82. For instance, if the contact pin 47 at-station '3 would require four cycles of the alternating current to bring it into bridging position, the station 4 would require five cycles of the current for this purpose and the station 5 would When the thumb wheel 3 has turned the indicator hand '12 to 5 on the dialgit has really moved the dog 12 six teeth over the ratchet because the hand- 1) has to move one space from the open l1ne POSltlOILtO the 0 character on'the series of numbers, so that such hand is really moved over six characters, that 1s. from open position, to 95, including zero position, and the: dog is correspondingly moved over six teeth.

Now, it should be borne in mind that the turning of the thumb wheel 3 to move the wise over the escape wheel 15 and also drops the latching rod 78 that engages pin 80 of escape wheel 43 of the receiving mechanism of the sending station 3 into positionto catch the escape wheel and prevent its extended rotation. This dropping of the latching rod 78, however, takes place only at the sending station 3, that is at the other.

two stations 4and 5, on the line the escape wheels 43 and their receiving mechanism will not be impeded against rotation because the latching rods are in their depressed position. Now, when the generator 9 is operated at station 3, what takes place is that the alternating current flowing through'the generator circuit to the alternating current coils 94 will vibrate or roc k the armature of the coils and consequently cause the armature rod 92 to vibrate from side to side and correspondingly vibrate the arm 89 which is connected with the vertical escapement bar 85. This bar in turn is rocked from side to side.

' when the pallet 87 leaves the tooth n the pin 8O strikes against the offset end,79 of the latch rod 78. Theconsequence is-that the escape wheel 43 is held against further rotation at this time by the latching rod 78 and the'contact pin 46 isa half step from the contact plates 81 and 82, that is to say it does not quite reach these plates to close the talking circuit at thispointQ Of course, at

this time the end of the pallet 87 of the escape rod 85 lies half way between the first and second teeth of the escape wheel 43 so that it may work idly sidewise during the time that the wheel 43 is held against rotation. At this time, therefore, the escape wheel 43 of the receiving mechanism of the sending station 3 is held against rotation,

while the escape wheel 15 of the sending" mechanism ofthe sending station 3 may operate under the step by step action of the escape rod 85 and pallet 87 when vibrated by the alternating current. At the same time the other two stations 4 and 5 only the escape wheels 43 of the receiving mechanisms may be rotated at these two stations and escape wheels 15 of the sending mechanisms -are in" their original positions which they occupy -when the line is clear, as shown in Figure 3, and the escapement pallet 87 rocks idly between the teeth of their wheels 15. Now, as the party calling continues to turn the crank of thegenerator at the station 3, he imparts six cycles of alternating current to the toils 94 and consequently completely vibrates the escapement bar 85 six times,-whi ch will bring the bar 11 and the dog 12 back to its original starting position at the sending mechanism of station 3, so that the pin 24 will again strike the arm 22, throwing this arm outward, rocking the shaft 19,. opening switches 25 and 84 and breaking the alternating current circuit as well as the bell circuit. The latching arm 78 at this time'is depressed moving the offset end 79 thereof out of the way of the pin 80 of the escape wheel 43 of the receiving mechanism at the sending station 3, permitting the contact pin 46 to pass to a position between the contact plates 81 and 82, and bridge or close the talking circuit as Well as the bell circuit at this point. It is to be understood that arm 11 carrying pin 24 is placed in' such position with relation to the arm 22 and escape wheel 15 that it opens the alternating current switch 25 between the negative and positive impulses of the current and thus compels the armature bar 93 of alternating coils 94 to stop vibrating with the same end resting on the coreevery time, and at every station on the line, and, of course, this rocks-shaft 85 to the left each time the circuit is broken, and this leaves pin 87 in an elevated position, both when a selection has been made and also when the line is clear. i

In the meantime, at the receiving mechanism of the called or receiving station 5, the escape wheel 43, which as stated was free to rotate under the action of the vibrating escape bar, has been stepped around six teeth or until the contact pin 47 bridged the contacts 81 and 82 and thus closed the talking circuit at this station 5'.

Now, while we, have connected the station 3 with the station 5, it will be evident that the station 4 could not have been connected because the only station which could be connected in the circuit at this time was station 5 which required six cycles of the alternating current, or six complete vibrations of the escapement device to bring the pin 47 into position between the contact plates 81 and 82 to close the talkingicira cuit. The intermediate station 4 on the line having its pin 47 set relatively closer to the pin 46 than is the pin' 47 to the pin 46' p of the station 5, such pin 47 of station 4 would, of course, reach the point between its contact plates 81 and 82 sooner than the pin 47 of the station 5 would reach its contact plates and consequently the continued action of the alternating current due to the continued operation of the generator, would move the pin 47 of the station 4 through the space between the contact plates 81 and 82 and beyond or past the same so that there would be no closed circuit at this point by the time the contact pin 47 of station 5 was in closed position, and as stated, this occurs y when the arm 11 at the sending station returns to its original positiom The parties 3 and may now hold their conversation with the other-party 4 on the line out out, because as stated the pin 47 bf party 4 .is not in position to close the talking circuit at the receiving side of this station. Of course, the operation of the generator at thesending station, causes the indicating hands 110 at the receiving dials of the stations 4 and 5 to both move to position to indicate thatthe phone 5 had been called and, therefore, all parties on the line will see that theline is busy because station 5 has been called.

Now, while the parties '3 and 5 are talking, it will be seen that, referring to the dial faces of the three stations on the line,

inthej sending station 3 the indicator hand w has moved one step upward or to the point ring ofi' and this shows that the pin 46 is 1n position between the contact plates 81 and 82 to close the talking circuit at the sending station. The indicating hand '0 of the sending station 3 has, of course, re-

turned to the position marked open line because the shaft 10 carrying the arm 11 with the dog 12 has returned to its normal positiongfrom which it started. On thedials of the stations 4 and'5 the indicating.

hands 'w, of the receiving mechanisms both -point to 5, the number of" the station I called, while tlie hands 4) of the'sending' line because the sending-mechanisms of these two stationshave not been disturbed.

mechanism of the other twostations 4 and 5 remain at the original position "offopen As the parties at the stations 3 and 5 are now ready; togconverse the talking circuit is closed and completed as follows: From the battery 104 the current flows through the conductor 111,-conductor 120 to. the transmitter t of'station 3, thence through the conductor 121, through the primary winding 122 of the induction coil'z', thence through the conductor 123 to the contact 124 of the re-' A ceiver switch, now contacted with by the circuit ust described sets up an induced curreceiver hook it forming apart of the switch. The current then passes through the receiver hook and conductor 105 back to the battery 104, I thus completing a primaryor trans mitter circuit. vThe same transmitter circuit, of course, is set up in the station 5 by the party at such statlon removing his receiver 1'. Now the primary or transmitter rent infthe secondary winding 125 of the induction coil 5, and from this winding the induced current flows-through the' conductor 126, through the condenser a, conductor 107,

part of conductor 27, contact plate 82, pin L 46, contact plateSl, part. of conductor 27,

' conductor 113- to the line wire a: and over the line wire to: the station 5, the current passing at station 5 through conductor 113,

' late 81, arena conductor 27 to the contact the pin 47 to the contact p ate 82, thenceto the conductor 27, to conductor 107, through the condenser 0, conductor 126, through-the secondary winding 125 at station 5,1through the conductor 127.1eading to the receiver 1' of station 5 through the receiver to the conductor 128 to the conductor 117 and back to the return 3 v the current flowing back through the return y from station 5 to station 3 where it passes down through theconductors 116 and 117 to the conductor 128 and back to the receiver 1*, thence through .the receiver and conductor 127 to the seccontact plates 81 and 82, as shown in dotted lines in said Fig. 1. At the same time. by reference to Fig. 1, it will be noted-that the contact pin 46 of the sending station 3 is .in position between the plates 81 and 82 to close the talking circuit of the station 3,

as shown in dotted lines, and the pin-47 has been moved between the contact plates 81 and 82 to close the talking circuit at thejlstation 5, as shown in dotted lines. Of course,

the contact pin 46 at the sending station 3-,

was locked by thelatch rod 78.1n its half stepped position and at the time the circuit of the generator was broken the latch '78 was removed an the contact 46. was permitted to move another half step to bridge I the contacts 81 and 82 by. reason of the escapement member 87 having stoppedin normal position, while-at the receiving-station .5, the escape wheel 43 was not held againste rotation, therefore, while the pin 46 was moved through and past the contacts 81 and 82 at station 5, the pin 47 was brought i by the six cycles of alternating, current into circuit closing position between the contact U plates 81 and s2.

Now, when the parties at the stations 3 and 5 have finished their conversation, the

line is cleared or restored to its position as follows: 1

The party at the sending station 3 first ronormal open tates the thumb wheel 3' to bring the hand v 1 rom its positionmarked open line to the sition marked ring off. I might menti that this rotation of the thumb wheel 3F'should take place before the receiver is hung up at the sending station 3, as otherwise, should the receiver be hung up first the localbattery bell circuit will clo e at station 3 and ring the bell at such station and thus acting as an indication to the party at station 3 that he has not cleared the line. In other words, I make provision for insuring that the partyat the station 3 will not through forgetfulness fail to clear the line after the conversation is finished, as the act of hanging up the receiver, ringing the bell, will act as an audible signal or warning that the line has not been cleared. Therefore, it is necessary to turn the thumb wheel 3 as the first act of clearing. When the talking circuit is closed and the conversation in progress, the locking arm 73 has occupied the position shown in Fig. 6 at the station '3, that is to say with the locking block 76 in its lowest position relative to the loop 23 of the arm Now, when the thumb wheel 3 is turned until the indicator hand 1) is at the position marked ring off in Fig. 1%,

tion shown in Fig. 3. This permits thespring 29 to turn the rock shaft and throw the arm 22inward so that the loop 23 straddles the block 76 as shown in Fig. 20, this again closing the alternating current cir-. cuit by the contact of the contact switch 25 with the contact pin 26. The party at the sending station 3 then turns the generator crank g, again setting up the alternating current, and as the alternating current circuit is closed the crank of the generator is turned to send a suflicient number of alternating current cycles over the alternating current circuit to cause the vibration of the escapement rod 85 to vibrate a suflicient number of times to move the arm 11 and dog 12 in the opposite direction or clockwise, thereby rotating the escape wheel 15 until the pin 24 on the arm 11 again reaches its normal or original position and strikes the loop 23 of the arm 22, thereby rocking'the shaft 19 and depressing the contact switch 25 again breaking thealternatin current circuit. It is to be understood t at whenthe circuit is closed by the contact switch 25 and pin 26 in clearing the line, and the generator operated, the escape" wheel 43 is rotated anti-clockwise under the action of the vibratingniovement of the escape bar 85 at the same time that the arm 11 is rotated clockwise or returning to its normal position. The result ofthe rotation of the two escapement wheels just described is that the parts are returned to the normal position shown in Fig. 3 with the indicator hands" at the sending station pointing to the position marked open line on the dial, while the in-; dlcating hand to at the stations 4 and 5 are both returned to the position-marked open line on the dials of the receiving mecha, nisms at those stations. Of course, at the stations 4 and 5 the hands 4) of the sending mechanism have not moved at all, as the sending mechanism has not been operated at these stations, while the alternating current cycles flowing through the coils 9 1 at the stations 4 and 5 have operated the escapement bars 85 at those stations to move the escapement wheel 13 ofthose stations anticlockwise to return the hands in to indicate the open line position on the dials. Of course, this would occur no matter how many stations were on the line.

The contacts 83 and 84 are necessary only to compel the party making the selection, to complete the operation of clearing up the line. For instance, the line is clear and in readiness for a call to be put through, pin 72 is engaging arm 71 which holds back 76 in central position of loop 23 which governs the operation of switch arms 25 and 8t fastened to post 19. When the station calling has removed the receiver from the hook and selected another station and when through with his conversation he must clear up the line or system, but in the event he should neglect to clear the line when he had hung up his receiver, his bell would ring through battery 104, conductor 111, 110, b, 109, 10s, pin 46, contact 82, 27 10?, 106, contact 103, hook h, 105 to battery.

The ringing-through the contact points 46 and 82, notifies him to clear the line, he must turn the thumb wheel 3, until the arm 11 engages the offset end 74, rod carrying locking block 76, arm 11 forces upward rod 74 until block 76 permits loop 23 to' pass over and allow the generator circuit to close throw contact point 46 out of engagement with 82 and, if the receiver is hung up without finishing the operation of clearing 'up (by turning the generator) the bell would ring as follows: 104, 111, 110, b, 109, 108, 84, 83, 27 107, 106, contact 103, hook it, to battery again.

The bell will continue to ring with the receiver on the hook until the generator is turned suificiently to return arm 11 until pin 24 engages arm 22 and opens the bell circuit point 83 and 84 and at the same time opens the generator circuit at points and 26.

Theabove is a complete description of the operation when two parties are on the line and it is not desired to have a third party cut in on the circuit. However, circumarties 3 and 5hold1ng a conversation to ave a third party, such for instance as the party at the station 4, take part inthe conversation and 1n thls instance it is, of course, neccssar to call this third party 4 and to puthim into with the escape wheel 43 so that this wheel will be held against rotation so long as the party continues to push the button 99 inward and consequently the contact pin 47 n at this'station will be held between the contacts 81iand 82 irrespective of anyclearing :of the line from the station 3,. because the contact pin 47 cannot .move as longas tlie wheel43 is stationary;- Now, after the arty at 5 has thus held his contact pin 47 against movement to keep his end of the talking circuit closed, the party at the sending station 3 turns his thumb wheel 3 around.- to the point marked ring 011' as before described, 7 jin clearin'gthe. line, then operates his gen the party at 5 who is still holding the con tact pin 47 to close the talking circuit at this erator g and thus clears the line as before described by operating the generator crank, that is the line is clear with the exception of station. The party at 3 ,then operates the thumb wheel 3*- again to turn out the indi-' cator hand '0 to the number of the station of v the third party, in the present instance numher 4,- and calls stati n 4 in the ordinary manner, as im calling he station 5, hereto-- fore described in detail. The station 4 is now on the circuit and as the cycles of the alternating current have ceased, the contact,

1 pins 47 of both stations 4 and 5 are closing the talking circuit at these stations, in ad dition to the bell circuit at station- 4, while the pin 46 at the station 3 is closing the talk ing circuit at that station: The consequence is that the party at station 4 is signaled by the closing ofhis bell circuit, as heretofore described for the closing of the bell circuit of the station 5, and as soon as he liftslthe 7 receiver all three parties may hold..acontversation. When they have.'' finished the party 3 clears the line in the ordinary maIIIIIQI'rJ/ IX" "21 I i The followin descnbes theuse and operation of the lock block 76" at jthe calling or sendi ngzstationv only, in the present instan ce,

' the station? Now it"wjll be seen that when theentire selecting-apparatus is at the-open position asjshown in Figs'3, the locking block 76 on thelocking' rod7 3 isheld oppositethe loop .23 of arm 22 by the engagement'of. arm 71 .60 escape wheel 43, and when the arm 11, car-, rying thepin 24 is moved aroundawayfrom engagementwith loop 23 of, arm, 22'itzwi with pin 72 which'is set in the rim of the permit loop 23 to straddle lockf'bliick f-76i o 1 locking rod 73, the .fsw-itch 25,

latching rod 78 and switch 84-, all bein fast with the rock shaft 19,-as shown in I lg. 3. Thlsshaft 19 moves clockwise under the ten- I slon of spring 29 until the ends of the switches 84 and 25 engage the contact pins 26 and 83. At this position the offset end 79 of the latching rod 78 is held in the' path "pin 80 of the escape wheel 43. -Now when the generator is operated and vthe current v flows it permits the rotation of escape wheel 15 but escape wheel 43 is only. permitted to rotate one step, or half the distance between two teeth n and m and the escape 'pallet87v vibrates idly because pin 80 engages offset end 79 of the latchingrod 78. But the es ,cape wheel 15 rotates until arm 11 carrying pin 24 engages loop 23 of arm'22 and moves it counterclockwise until it engages stop pin 30. Therefore the arm- 22, "switch 25, switch 84 and rod 78 all move in unison and thus it will be seen that the switch 25 movesaway from pin 26 which breaks the alternating current circuit. At the same instant the switch 84 moves away from the pin 83 which breaks the bell circuit at that point; also the latching rod 78 carrying offset 79 is disengaged'from pin 80 of escape wheel 43 and. 10( the escape'wheel'is then permitted to rotate until the escape tooth rests against the pallet 87. The rotation of the escape wheel 43 from tooth n to tooth m hasbrought the pin 72} in such a, position inc describing a 10.5

circle that it now moves arm 71 a little to the left and this causes locking'rod 73 to move downward, the arm 11 carrying pin 24- having moved loop 23 back out of the way, as shown in Fig.6. This pennits lock turned around sufiiciently to permit enough cycles of current to pass to cause the escape wheel 43 to rotate to the blank space 51- in its rim and it will. be seen that when the arm ll is turned around until pin 24 engages'hook 74 of the locking rod "73,-it-

springs this rod 73 upward until loop 23. of arm 22 again straddles block 76, and'thus again rotates rock shaft 19 which inturn moves the switch 25 into contact with pin 26,

also moves end of switch-84 intocontact with I pin..83 and also moves rod 7 8'with 'ofi'set; end I pward, but this oflset end 79 doesnot' engage pin 80, as such end comes, up

behind the pin 80. Now when the generator is again operated both escape wheels 15-and 

